Looking for an idiom that means “inexperienced or lacking knowledge"

[Adam_C]

Hi,

I’m looking for a bunch of idioms which mean to be inexperienced in something or lacking the correct knowledge.

The only one I’ve been able to think of so far is “out of my depth” but I would prefer a bunch of them to be able to pick the right one. If anyone can think of any others I’d be very grateful!

Thanks.

[emsr2d2]

In over one's head
Wet behind the ears

[Tdol]

If someone is green/a greenhorn, they are inexperienced.

[Matthew Wai]

Novice, newbie and rookie have a similar meaning, according to dictionaries.

Not a teacher.

[Emmanuel Chevassus]

"Shortcomings" = "a lack of knowledges"

[BillHaverberg]

Shortcomings often means someone has character or personal issues like laziness or a bad attitude; it's not good to use that for someone who is merely inexperienced.

[Barb_D]

"Shortcomings" = "a lack of knowledges"

"Knowledge" is not countable.

[probus]

A tyro

[Matthew Wai]

lacking the correct knowledge.

'Ignorant' means 'having no knowledge or awareness of something or of things in general'── quoted from http://dictionary.cambridge.org/dictionary/american-english/ignorant?q=ignorant

Not a teacher.

[Tdol]

But ignorant often has a negative connotation and can be insulting.